Gas operated switch



Oct. 11, 1932. M. A. LASWELL 1,881,710

GAS OPERATED SWITCH Filed May 20. 1929 f/vm/vrm Ma 00nd ,4. ZdSIV8// l49 6r 1/ l I 6' (4K M A rrvmvsr Patented Oct-11, 1932' UNITED. STATESPATENT OFFICE MAYNARD A. LASWELL, OI LOS ANGELES, CALIFORNIA, ASSIGNORTO BWINGS POUT MEASURE COMPANY, OF LOS ANGELES, CALIFORNIA, ACORPORATION 01 CALIFORNIA.

GAS OPERATED SWITCH Application and m 20, 1929. Serial No. 864,676.

My invention relates to a new. and novel type of electrical switch whichis operated by a fluid pressure. e

My device is particularly adapted for use i F with fire extinguishingapparatus, although it is not confined to this use alone, as it may beused in other ways. It is particularly adapted for use with fireextinguishing apparatus of the type installed in buildin s or otherstructures where the fire extinguis ing fluid or gas is supplied underpressure to distributing points in the buildings or structures.

In the operation of this type of fire extinguishing apparatus, it isoften desirable to have the release of the extinguishing fluidaccompanied by the switching of an electrical circuit, whic may be usedto open an electrical circuit breaker so as to de-energize the powerlines to the building, to close a circuit and sound an alarm, or forsimilar operations.

It is an object of my invention to provide an electrical switch havingsufiicient capacity to switch the pilot circuit of an electrical deviceand which will be automatically operated by the pressure of theextinguishing fiud when the latter is supplied to extinguish a re.

In the operation of this switch, it is desirable to have the switch stayin the operated position until reset by hand, so that the operator mayascertain whether or not the electrical circuit is in the propercondition before 1 resetting the switch. This is known as the hand-resettype of switch.

It is another object of my invention to provide a switch which will havethe hand-reset features.

In order to reduce the cost of manufacturing a switch of the above type,it is desirable to have a simple means w ereby the switch may be changedto make it open or to make it close an electrical circuit when it isoperated.

In other words, the switch must be readily convertible into acircuit-opening or circuitclosing type.

It is a further object of my invention to produce a switch which may bereadily converted into the circuit-opening or circuit-clos- 1ng type.

When such a switch is installed so as to operate with fire extinguishingequipment, as mentioned above, the installation and o eration of theswitch must not interfere Wit the release of the fluid in the building,as it would impair the efficiency of the fire extinguishing. system.

It is another object of my invention to provide a switch whereby theinstallation and o eration of'such will not interfere with t eefiiciency of the apparatus to which it is attached.

Further objects of my invention will ap pear in the followingdescription.

In this description and in the accompanying drawing I show a preferredform of my switch attached in a pipe line of a fire extinguishing systemof the type before mentioned. The pipe line illustrated is a linesupplying extinguishing fluid under pressure to distributing outlets.The switch is operable by the pressure of the fluid in the line. Asmentioned before, my device may be used with other apparatus than thatillustrated.

In the accompanying drawing:

Fig. l is a side elevation of myin'vention showing a partial sectionthereof.

Fig. 2 is a sectional view taken on the line 22 of Fig. 1.

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 1.

Fig. 4 is a side elevation showing the appearance of the switch.

Referring to the drawing, my invention consists of a box-shaped housing11 having an open front which is covered by a glass 12. The glass 12 isretained in place by a cover 13 secured to the housing 11 by suitablemeans such as screws 14. In order to permit a view of an enclosureformed by m with the enclosure 15. A cylinder is secured to the housing11 by a sleeve 2l formed A of the cylinder 20 form an axial openin 22 inthereon which is adapted to fit into the opening 18 in the flange 17 andwhich is secured therein by a set-screw 19 threadedly inserted throughthe walls of the flange 17. The walls which a piston 23 is movablyposltione Secured to the piston 23 is a piston rod 24 which passesaxially upward through the openlng g0 22, through the opening formed bythe walls of the sleeve 21, and into the enclosure 15. The walls of thesleeve 21 have a smaller 1nside diameter than the walls of the cylinder20 and form a guide bearing for the piston '5. rod 24. The plston 23 andthe piston rod 24 form the operating means of my invention.

The lower end of the cylinder 20 is threadedly secured to a thick-walledpipe 26 so that the axial opening 22 in the cylinder 20 is at rightangles to the axis of the pipe 26 and communicates with an axial opening28 formed by the walls thereof. To the ends of the pipe 26 are securedasupply pipe 29 and an out-let pipe 30 by unions 31 in the 5 usualmanner. This arrangement provides a passage for a fluid from the supplypipe 26 through the opening 28 to the outlet pipe 30 and through theside opening 22 to the piston 23. This allows the fluid in the pipe 26to be transmitted to the piston 23 without interfering with the flowthereof.

To the upper end of the piston rod 24,

' which extends into the enclosure 15, is secured a switch mechanism,which consists of 4.5 a rod 33 having a bore 34 at its lower end adaptedto accommodate the upper end of the piston rod 24, the piston rod 24being retained in the bore 34 by a pin 35 which passes through a hole 36formed through the no walls of the rod 33 and'through the piston rod 24.The rod 33 forms an extension of the piston rod and extends upwardlythrough the enclosure 15, through an opening 37 formed in the upper wallof the housing 11 and outside of the housing 11. To the upper end of therod 33 a handle 38 is threadedly attached, which handle 38 provides ameans for manually operating the switch mechanism. To the lower end ofthe rod 33 a cylinder 40 of insulating material is secured by the pin 35which passes through holes in the walls thereof.

The cylinder 40 has a reduced diameter at its upper end for receivingthereon the walls of a tight-fitting cylinder 41 of conducting eannematerial which has an outside diameter equal -the cylinders 40 and 41and consists of a block 44 of insulating material secured to an insidewall of the housing 11 by suitable means.

such as screws 45. Secured to the blocks 44 are conductors 46, whichextend through openings 48 formed in the housing 11, of suflicient sizeto permit the conductors 46 to pass therethrough without contacting thewalls thereof. At the outer end of the conductors 46 are screws 49 forthe pur ose of attaching electrical wires thereto. ecured to theconductors 46 at a point near the inner wall of the housing 11 arehorizontal springs 51, to the movable ends of which are secureddisc-shaped contacts 52 by swedged pins 53. The springs 51 with theattached contacts 52 are positioned so that the contacts 52 contact theconducting cylinder 41 and complete an electrical circuit between theconductors 46 when the mechanism is moved downwardly, as shown in Fig.1, and contact the insulating cylinder 40 and open the electric circuitwhen t in Figs. 2 and 4.

The switch is in the normal position when the mechanism is moveddownwardly, as shown in Fig. 1, in which position the electrical circuitis closed between the conductors 46, and an operation of the mechanismupward to the osition shown in Fig. 2 opens the switch. This constitutesa circuit-opening switch. In case a circuit-closing switch,

is desired, the relative positions of the cylinders 40 and 41 aretransposed so that the electric circuit is open when the mechanism is inthe normal position and closed when the mechanism is in the operatedposition.

- When the device of my invention is used withfire extinguishingequipment, electrical connections are made to the conductors 46 by meansof screws 49,- and the mechanism is moved to the normal osition shown inFig. 1. When the fire extinguishing fluid is supplied to the pipe 26,the pressure of the fluid acting on the piston 23 moves the mechanismupwardly, and the electrical circuit e mechanism is moved upwardly, asshown between the conductors 46 is opened as explained before. Themechanism is maintained in this position by the friction of the contacts52 with the cylinder 40 until it is manually reset by moving themechanism downwardly.

It will be noted that my device may be I operated by hand or by anysuitable pressure means applied to the piston 23. It is thereforeadaptable to other apparatus than that specified herein.

I claim as my invention:

1. In a switch of the character described, a fitting for connection in afluid conduit, a cylinder in communication with the fitting, a pistonoperable in the cylinder, a housing supported by the cylinder and havinga sight opening at one side, a stem on the piston extendin through thehousing and projecting from t e housing for manual operation, astationary contact in the housing, and a contact on the stem tocooperate with the stationary contact, the contact being visible throughthe sight opening.

2. In a switch of the character described, a fitting for connection in afluid conduit, a part connected with the fitting to project laterallytherefrom, said part having a large bore communicating with the fittingand a small bore in its outer portion, a piston operable in the largebore, a housing mounted on the outer portion of the said part and havinga sight openin with a transparent closure, a stem on the plston slidablfitting the small bore and extending throng the housing and projectingfrom the housing, a stationary contact in the housing, and a contact onthe stem to cooperate with the stationary contact,

the contacts being visible through the sight opening.

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 14th day of May 1929. v I

MAYNARD A. LAswELL.

